Portable electric rotary drain cleaners have been around for more than seventy years. U.S. Pat. No. 2,467,849 to John V. O'brien, et al. describes a device having a pistol-grip handle coupled to a hollow barrel, an electric motor assembly positioned in front of the handle below the barrel, a chuck at the distal end of the barrel that is coupled to the motor assembly via a gear drive, and a flexible cable that passes through the handle, enters the barrel, and exits through the chuck. An appropriate portion of the cable can be extended through the chuck opening and, with the chuck tightened so that it clamps the cable to the gear drive, the cable will be axially rotated when the motor assembly is activated.
U.S. Pat. No. 2,769,191 which issued to Robert G. Hunt, et al. In 1954 (some ten years later) discloses a Plumber's Tool, a similar machine having a rotating drum that houses an unused portion of the drain cleaning cable. U.S. Pat. No. 3,206,782 to John H. Larsen discloses a Plumber's Snake Device that improves on the device of the '191 patent. Though equipped with a unidirectional motor, the Larsen device provides the operator with a simple controller to effect change between feed and retraction while the motor is operating. In addition, the controller enables the operator to halt feed or retraction of the snake while the motor is operating. The device also automatically stops the feed when the free end of the snake encounters an abnormal obstruction in the pipe being cleaned. In addition, retraction of the snake is automatically stopped when it comes to a fixed stop. U.S. Pat. No. 3,224,024 to Robert G. Hunt discloses a portable powered plumber's snake having an alternative feed mechanism.
Most of the ultra-portable powered plumber's snakes incorporate what appears to be an electric drill motor. Realizing the limitations of such a device, U.S. Pat. No. 3,268,937 to Burton J. Bollinger has packaged such a portable unit in a box, while providing an external switch for the operator.
The Plumbers' Tool described in U.S. Pat. No. 3,609,788 to Mark F. Mier is a plumbers' flexible snake having a chuck through which the snake passes in and out, an adapter shell suitable for mounting on a motor or on a crank which releasably attaches to the rear of the container to afford a means for rotating the container, and a container adaptable for mounting various types of chucks.
U.S. Pat. No. 4,218,802 describes a Drain Cleaning Apparatus that utilizes a flexible snake which is inserted into a drain pipe and rotated so as to cut through a blockage or obstruction in the drain pipe. The apparatus includes a manually actuated chuck operable while the apparatus is in operation, for holding the snake relative to the apparatus, thus enabling the operator to feed the snake forceably into the drain pipe and into cutting engagement with an obstruction, and auxiliary means operable to lock the snake securely with respect to the apparatus so as to perm it the torque of the apparatus' drive motor to be applied to the snake.
U.S. Pat. No. 4,763,374 to Paul S. Kaye discloses a powered drain-cleaning implement of the type with a rotatable snake extendable for drain insertion. The device has a housing with a rear portion over the motor and a front portion terminating in a collar, a snake container rotatably supported in the front portion and having a forward tubular portion extending through the collar and ending in a distal opening where the snake is adjustably secured, a ring gear on the back of the container, and a pinion gear on the motor engaging the ring gear for high-torque rotation of the snake. The housing preferably covers the motor, gears and container. Its rear portion preferably has a handle and associated trigger for easy holding and operation.
A Portable Drain Cleaning Apparatus is disclosed in U.S. Pat. No. 4,956,889 to Karl L. Kirk, which is of the type employing a flexible snake which is rotated and inserted into a waste line to remove blockage. The apparatus includes a housing in which the snake is coiled and a guide tube extending from the housing and through which the snake passes for insertion into a waste line. A manually actuated sleeve assembly is provided on the guide for displacing resilient spring finger clamping elements into engagement with the snake to hold the snake against axial displacement relative to the housing during insertion and/or removal of the snake from the waste line and to clamp the snake against rotation relative to the guide tube and the housing during the drain cleaning operation. The sleeve assembly is removably retained on the guide tube, and the spring finger elements, the guide tube and the sleeve assembly engage with one another to alone removably support the spring finger clamping elements against axial and circumferential displacement relative to and radial separation from the guide tube. Upon removal of the tubular hand grip, the spring finger gripping elements are released for separation from the guide tube.
It will be noted that the drain cleaning device of the '849 Patent to O'brien, et al., as well as more modern drain cleaning devices, such as the device of the '889 Patent to Kirk, are derivatives of the Drain Cleaner that is the subject of the 1940 U.S. Pat. No. 2,284,939 to Remi C. Asnard. The Asnard patent discloses a hand-cranked drain cleaner which includes a plumbers' snake that is stored in a container and which has one end protruding through a central hole in the container. The snake, which can be extended and retracted through the hole, can also be rotated—along with the container—by rotating the hand crank.
A main problem with the foregoing devices is that they have what may be characterized as a pistol grip. Thus, using such a device is like holding a pistol with a thirty-pound weight suspended from the end of the barrel. Using conventional portable motorized drain cleaning machines can not only be tiring, but can result in soft tissue damage to the wrist, elbow and shoulder joints of the user.